Slashdot Mirror
A Baffling Brain Defect Is Linked to Gut Bacteria, Scientists Say (sciencealert.com)
Gina Kolata from The New York Times writes about a baffling brain disorder that is linked to a particular type of bacteria living in the gut (Warning: source may be paywalled; alternate source) The new study, published on Wednesday in Nature, is among the first to suggest convincingly that these bacteria may initiate disease in seemingly unrelated organs, and in completely unexpected ways. The researchers studied hereditary cerebral cavernous malformations -- blood-filled bubbles that protrude from veins in the brain and can leak blood or burst at any time. When Dr. Mark Kahn, professor of cardiovascular medicine at the University of Pennsylvania's Perelman School of Medicine, began this work, the microbiome was the last thing on his mind. Dr. Kahn and his colleagues studied cerebral cavernous malformations as part of a larger effort to understand the development and function of blood vessels. Three genes have been linked to the disorder, and Dr. Kahn and his colleagues tried to figure out what these mutations really do. The scientists were able to mimic the condition in mice by deleting a gene that is mutated in many patients. A year ago, the scientists moved to a new building, and something unexpected happened. The experimental mice stopped developing the brain malformations. Dr. Kahn's student, Alan T. Tang, had been deleting the gene by injecting a drug into the abdomens of the mice. Sometimes a mouse would get an infection that would lead to an abscess, and bacteria leaked from the gut into the blood. In the new building, only those mice still developed the brain defect. The other gene-deleted mice did not. He and his colleagues finally identified the culprit: Gram-negative bacteria, named for the way they stain, that carry a molecule in their cell walls, a lipopolysaccharide. Without a functioning gene, the lipopolysaccharide can signal veins in the brain to form blood bubbles.
Parkinson's has some connections to the gut. For instance, it is correlated with constipation. Also people who drink a lot of coffee or tea are less likely to be afflicted. But I don't think it is cause by bacteria, because there is no cure. If gut bacteria caused the disease, some people would be cured inadvertently when they take high doses of antibiotics for other reasons, and that doesn't happen.